Anti-angiogenic effects of mammalian target of rapamycin inhibitors in a mouse model of oxygen-induced retinopathy.

Abstract

Ocular pathologic angiogenesis is a causative factor for retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration. In the present study, we examined the effects of rapamycin and everolimus, inhibitors of mammalian target of rapamycin (mTOR), on retinal pathologic angiogenesis in mice with oxygen-induced retinopathy (OIR), an animal model of proliferative ischemic retinopathy. Mice were exposed to 80% oxygen from postnatal day (P) 7 to P10, and were then brought into room air and subcutaneously injected with rapamycin and everolimus. The neovascular tufts, the size of the central avascular zone, and the immunoreactivity for phosphorylated ribosomal protein S6 (pS6), a downstream indicator of mTOR activity, were evaluated in flat-mounted retinas. Retinal neovascular tufts and vascular growth in the avascular zone were observed in P15 mice with OIR. In addition, intense immunoreactivity for pS6 was detected in the neovascular tufts and in endothelial cells located at the vascular-avascular border. Both rapamycin and everolimus reduced the extent of retinal neovascular tufts and pS6 immunoreactivity, but they also increased the size of the avascular zone. Thus, activation of the mTOR pathway in endothelial cells contributes to retinal pathologic angiogenesis, and mTOR inhibitors that target proliferating endothelial cells are promising candidates as anti-angiogenic agents for the treatment of vasoproliferative retinal diseases.

• Authors: Rina Yagasaki, Tsutomu Nakahara, Hiroko Ushikubo, Asami Mori, Kenji Sakamoto, Kunio Ishii
• Journal: Biological & pharmaceutical bulletin (Biol Pharm Bull) Vol. 37 Issue 11 Pg. 1838-42 ( 2014) ISSN: 1347-5215 [Electronic] Japan
• PMID: 25366488 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Angiogenesis Inhibitors
• Everolimus
• mTOR protein, mouse
• Ribosomal Protein S6 Kinases
• TOR Serine-Threonine Kinases
• Oxygen
• Sirolimus

Topics

• Angiogenesis Inhibitors (pharmacology, therapeutic use)
• Animals
• Everolimus
• Mice, Inbred ICR
• Oxygen
• Retina (drug effects, metabolism, pathology)
• Retinal Neovascularization (drug therapy, etiology, metabolism)
• Ribosomal Protein S6 Kinases (metabolism)
• Sirolimus (analogs & derivatives, pharmacology, therapeutic use)
• TOR Serine-Threonine Kinases (antagonists & inhibitors)